It is common medical practice today to implant stents within the body to maintain openings within certain passages therein. For instance, a biliary stent might be implanted to ensure drainage through an obstructed bile duct. Stents are configured in a variety of shapes and sizes, depending upon the location and purpose of the intended implantation, and the personal preference of the attending physician.
When a stent needs to be replaced or removed, prior to the present invention, the procedure for removal has been standardly performed with the use of retrieval forceps, baskets, or snares. Such devices are used to grasp the proximal end of the implanted stent. After the stent has been firmly grasped, it is pulled through the duct and out of the body.
There are several attendant disadvantages with this heretofore commonly used practice for removing implanted stents from within the body. For one thing, the actual process of technically grasping and pulling the stent out of its implanted position evenly and atraumatically can sometimes be difficult to perform, particularly for the larger sized stents. Where the stent has not been and pulled out evenly, bleeding and/or scaring can result, which can cause trauma and possible aggravation of the problem of occlusion that is being treated. Yet another significant complication concerns the fact that, when grasped by a retrieving device, the stent will most often not fit within the channel of the endoscope. The endoscope must therefore be removed in order to allow for the retrieval of the stent, and then be repositioned again for the replacement procedure. The requirement of recannulation adds considerable time to the overall replacement process.
Implanted stents need to be regularly removed and replaced since they, themselves, tend to become occluded after a period of time. Owing at least partially to the relative difficulty involved in replacement, much has been done in the way of attempting to extend the useful life of an implanted stent. What is needed is an improved method and apparatus for removing stents that have been implanted within the body, which would facilitate replacement in an atraumatic way.